CONDENSED STATEMENT OF STOCKHOLDERS' EQUITY (DEFICIT) - USD ($)	New Accounting Pronouncement Early Adoption Effect Additional Paid-in Capital [Member]	New Accounting Pronouncement Early Adoption Effect Retained Earnings [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss)	Retained Earnings [Member]	Total
Balance at beginning of period at Dec. 31, 2015					$ (79,399)
Net income (loss)							$ (32,822,796)
Unrealized loss on securities							111,039
Balance at end of period at Sep. 30, 2016					31,640
Balance at beginning of period at Jun. 30, 2016					96,246
Net income (loss)							(8,707,396)
Unrealized loss on securities							(64,606)
Balance at end of period at Sep. 30, 2016					31,640
Reclassification of impact of ASU 2016-09 (See Note 3) | ASU 2016-09	$ 267,824	$ (267,824)
Balance after adjustment			$ 42,378	$ 391,036,566	(41,196)	$ (253,890,385)	137,147,363
Balance at beginning of period (Previously Reported) at Dec. 31, 2016			$ 42,378	390,768,742	(41,196)	(253,622,561)	137,147,363
Balance at beginning of period at Dec. 31, 2016					(41,196)		137,147,363
Balances (in shares) (Previously Reported) at Dec. 31, 2016			42,377,522
Balances (in shares) at Dec. 31, 2016			42,377,522
Exercise of stock options			$ 52	109,690			109,742
Exercise of stock options (in shares)			52,258
Stock-based compensation			$ 115	2,586,131			2,586,246
Stock-based compensation (in shares)			114,365
Employee stock purchase plan			$ 37	48,370			48,407
Issuance of common stock in connection with development and license agreement			$ 2,000	2,818,000			2,820,000
Issuance of common stock in connection with development and license agreement (in shares)			2,000,000
Issuance of common stock in connection with exercise of warrant to purchase common stock			$ 3,278	5,501,925			5,505,203
Issuance of common stock in connection with exercise of warrant to purchase common stock (in shares)			3,278,000
Number of shares purchased under ESPP			37,236
Net income (loss)						(46,500,131)	(46,500,131)
Unrealized loss on securities					36,636		36,636
Balance at end of period at Sep. 30, 2017			$ 47,860	402,100,682	(4,560)	(300,390,516)	$ 101,753,466
Balances (in shares) at Sep. 30, 2017			47,859,381
Balance at beginning of period at Jun. 30, 2017					(34,863)
Exercise of stock options (in shares)							0
Net income (loss)							$ (23,266,818)
Unrealized loss on securities							30,303
Balance at end of period at Sep. 30, 2017			$ 47,860	$ 402,100,682	$ (4,560)	$ (300,390,516)	$ 101,753,466
Balances (in shares) at Sep. 30, 2017			47,859,381